Measurement Path Planning Research Articles

Kinematics characterizing with dual quaternion and parametric modeling of geometric error terms based on measuring path planning of CNC machine tools

Kinematics characterizing with dual quaternion and parametric modeling of geometric error terms based on measuring path planning of CNC machine tools

Genetic Algorithm Based Path Planning for Seawater Depth Data Measurement in Real Scenarios

In this paper, firstly, the movement direction of the measuring ship is clarified, and according to the requirements of factors such as the range of overlap rate is controlled at 10% to 20% and the sea area is completely covered, the optimization equation system is derived, and the objective function is derived through the requirements, and the optimal solution can be derived from the two associations as the 34 measuring lines and the total length of 68 nautical miles of the shortest measuring lines. Using genetic algorithm to examine the real scene of seawater depth data measurement path planning, the length of the measurement line and coverage as an assessment index of the algorithm's subsequent optimization of the object of choice. Through the simulation of genetic mutation, crossover and selection operations, the total length of the shortest survey line is 21.5261 nautical miles, the percentage of missed sea area is 1.6%, and the overlap rate is 13.12% after the iterative solution of the genetic algorithm.

Adaptive Ant Colony Optimization with Sub-Population and Fuzzy Logic for 3D Laser Scanning Path Planning.

For the precise measurement of complex surfaces, determining the position, direction, and path of a laser sensor probe is crucial before obtaining exact measurements. Accurate surface measurement hinges on modifying the overtures of a laser sensor and planning the scan path of the point laser displacement sensor probe to optimize the alignment of its measurement velocity and accuracy. This manuscript proposes a 3D surface laser scanning path planning technique that utilizes adaptive ant colony optimization with sub-population and fuzzy logic (SFACO), which involves the consideration of the measurement point layout, probe attitude, and path planning. Firstly, this study is based on a four-coordinate measuring machine paired with a point laser displacement sensor probe. The laser scanning four-coordinate measuring instrument is used to establish a coordinate system, and the relationship between them is transformed. The readings of each axis of the object being measured under the normal measuring attitude are then reversed through the coordinate system transformation, thus resulting in the optimal measuring attitude. The nominal distance matrix, which demonstrates the significance of the optimal measuring attitude, is then created based on the readings of all the points to be measured. Subsequently, a fuzzy ACO algorithm that integrates multiple swarm adaptive and dynamic domain structures is suggested to enhance the algorithm's performance by refining and utilizing multiple swarm adaptive and fuzzy operators. The efficacy of the algorithm is verified through experiments with 13 popular TSP benchmark datasets, thereby demonstrating the complexity of the SFACO approach. Ultimately, the path planning problem of surface 3D laser scanning measurement is addressed by employing the proposed SFACO algorithm in conjunction with a nominal distance matrix.

Deep learning–based intelligent measurement methods and system for CMM

Extensive manual intervention and management are typically required when using coordinate measuring machines (CMMs) for inspections in production lines leading to low efficiency. This study presents a deep learning–based intelligent measurement method and system for measuring typical features (including holes, cylinders, balls, steps, and slots) of common components to improve inspection efficiency. This method combines vision sensors and a trigger probe. The You Only Look Once algorithm was employed to learn and achieve intelligent detection of features. An image-matching algorithm based on image inverse perspective transformation was designed, and the ant colony algorithm was implemented to optimize the measurement sequence. Then, an automatic approach for feature measurement path planning was designed. The presented system was tested using CMM, and a component with multiple typical features was measured. Results show that this method and system can be efficaciously implemented for intelligent measurement of typical features.

A measurement point planning method based on lidar automatic measurement technology.

The automated measurement mode in the lidar measurement system (LMS) has advantages unmatched by other measurement equipment in measuring the surface of large components. Before starting the automatic measurement mode, it is necessary to plan the measurement guide points for the measurement area. The rationality of the measurement points planning will directly affect the quality of the measurement data and the measurement efficiency. This paper proposes a planning method for measurement points on the outer surface of components based on lidar automatic measurement technology. First, the geometric features to be measured are discretized into spatial point cloud data. Second, the edge points of the point clouds are extracted and indented to meet the measurement requirements, which improves the measurement accuracy of the edge areas. Finally, by planning the path of the measurement points, the laser beam of the lidar can traverse the points of the measurement features with the shortest paths. Through the analysis of two cases, the method proposed in this paper will provide a huge advantage for the LMS: (1) The edge points of all features can be identified and indented in a short time to ensure the measurement accuracy of the edge areas of each measurement feature. (2) Through the measurement path planning, the repetitive measurement path of the lidar can be significantly reduced, improving the measurement efficiency. The method proposed in this paper has important guiding significance for the subsequent measurement station planning and constructing large-scale spatial measurement fields of the LMS.

A Digital Twin-Based Intelligent Robotic Measurement System for Freeform Surface Parts

This paper proposed a novel framework of a digital twin-based robotic measurement system for freeform surface parts, which can improve the efficiency, autonomy, and intelligence of the robotic measurement system. This framework provides core services for robotic measurement tasks including visibility computation, collision detection, sensor simulation, path planning, and 3D inspection. These services improve the adaptability and the simulation capability of digital twin-based robot measurement system for freeform surface parts. Based on the proposed framework, an effective viewpoint planning method combining viewpoint sampling strategy and nest-best-view planner (VS-NBV) for freeform surface parts is proposed and verified. And case studies demonstrated the advantages of the digital twin-based robotic measurement system in terms of viewpoint planning, measurement path planning, object reconstruction, and 3D inspection.

A novel cable-grasping planner for manipulator based on the operation surface

The manipulation of deformable linear objects is a hot spot and difficult problem in robotics research. Cables, as one kind of deformable linear objects, are characterized by elongation and uncertain shape. Although previous research has paid attention to deformable linear object’s manipulation, it still remains a challenge to detect and grasp cables in unstructured environments. In this paper, a new cable-grasping method framework by analysis of cable characteristics is proposed. The framework consists of cable pose measurement and cable-grasping path planning. In the cable pose measurement mission, we design a symmetric edge feature according to the cable image projection principle. Then, a semantic segmentation based edge detection technique and a center line fitting method based on sorting by principal axis are applied to measure the cable pose accurately. In the cable-grasping path planning mission, the grasping pose is determined considering the force directional manipulability . The cable operation surface is constructed after the characteristic analysis of the cable, on which basis, a two-phase path planner is proposed, with the second phase planner BG-RRT guided by motion directional manipulability to further optimize the planning path. The performance of the approach is verified by experiments in both the simulation environment and the actual environment. • Proposing a symmetric edge feature based on the cable image projection principle. • Designing an edge detection method based on semantic segmentation as well as a center line fitting method based on sorting by principal axis. • Constructing the cable operation surface according to the characteristics of cable. • A two-phase path planner based on operation surface for reducing collisions. • A new BG-RRT algorithm guided by motion directional manipulability for further improving the efficiency of cable grasping.

Research on Robotic Measurement Path Planning for Complex Surface Workpieces

Combined with measurement efficiency, measurement accuracy and no interference in the measurement process, this paper proposes a path planning method for a measuring robot for complex surfaces such as blisk. The position planning of robot measurement path is realized based on the surface chord height difference, and the attitude planning of robot measurement path is realized based on the single measured point measurement attitude space(SMPMAS). Finally, the effectiveness of the proposed method is verified by experiments.

Analysis of factors affecting measurement accuracy and establishment of an optimal measurement strategy of a laser displacement sensor

Laser triangulation method is widely used in online precision measurement owing to its advantages of being fast, accurate, and dynamic, and having large-scale measurement capability. To improve the accuracy of laser triangulation, the scan depth, inclination angle, rotation angle, and deflection angle are defined. Then, a spatial pose error model and an experimental model for laser measurement error are established. Next, error analysis experiments are conducted, and the influence of spatial pose parameters on the error is analyzed. Further, error proofreading experiments on the surface characteristics of the measured workpiece, including the material, surface roughness, and color, are completed, and their influences on the error are analyzed. Based on the experimental data, an error correction model based on support vector regression is established. Measurement strategies are formulated considering multi-factor constraints such as optical path interference, mechanical interference, scan depth of field, measurement angle, and measurement path. The tooth profile of a cycloid gear is taken as the measurement object, then the measurement path planning is performed, and the error correction model is used to correct the measured data. The accuracy of the results agrees well with the result of a fully automatic computer numerical control (CNC)-controlled P 65 precision measuring center.

A Form-Free and High-Precision Metrological Method for the Twist of Aeroengine Blade

In order to solve the problems in the accuracy and adaptability of the existing methods for blade twist measurement, a high-precision and form-free metrological method of blade twist based on the parameter evaluation of twist angular position and twist angle is proposed in the study, and the theoretical model, the measurement principle and the key technologies of the method are discussed in detail. Three key issues of the twist metrology of a blade are solved based on technologies of calibration, a priori planning and geometric analysis: aeroengine axis matching, high-precision coordinate acquisition of the leading edge and the trailing edge, and extraction of twist angular position of the profile. The measurement path planning, sampling strategy optimization and high-precision coordinate collection are executed automatically without theoretical model data of the measured blade, thus the form-free and high-precision metrology of the blade twist is achieved. The research results show that the metrological method of blade twist presented in this study is effective, and that its measurement uncertainty is less than 0.01°. This method is form-free, efficient and accurate, and can solve the problems of high-precision measurement and evaluation for the twist of aeroengine blade primely.

An adaptive-group-based differential evolution algorithm for inspecting machined workpiece path planning

In the precision manufacturing process, accuracy and precision are crucial when designing a workpiece inspection system. An efficient system minimizes inefficiencies caused by workpieces failing to meet customer needs and delays caused by slow workpiece inspection. In this study, a workpiece inspection system for measuring path planning is proposed that uses the given coordinate of inspection points discerned from 3D images. Then, an adaptive-group-based differential evolution (AGDE) algorithm is used to optimize the measuring path. The AGDE algorithm incorporates the grouping concept into conventional differential evolution, and this improves local search ability through referencing the direction of the best solution in each group. By using the proposed method, the shortest non-colliding measuring path is obtained. Moreover, the proposed workpiece inspection system shortens the workpiece inspection time and achieves faster performance than manual measuring path planning under multiple workpiece inspection points.

Research on measurement path planning of complex object

In the past automatic measurement system for three-dimensional shape of complex parts, there was no corresponding measurement scheme for the groove-shaped complex parts, which there existed problems such as low work efficiency and large measurement error. In order to solve this problem, this paper is based on the principle of raster scanning projection measurement, and explores the mathematical model of projection grating trigonometry theory, and analyzes the different characteristics of scattered geometric features such as walls and edges inside the groove in complex parts. Combined with the scanning constraints such as the inclination angle and depth of field of the 3D scanner, the method of measuring the path planning of the groove-shaped complex parts was proposed and studied. Finally, the measurement path planning verification experiment was carried out, which is based on the above analysis. The results show that the position deviation during the measurement process is within 0.001mm, the angular deviation is within 0.009°, which proves the feasibility of the measurement path for the groove-shaped complex parts.

Surface reconstruction of laser-cladding remanufacturing blade using in adaptive belt grinding

The remanufacturing technology of aero-engine blade is one of the effective ways to save expensive materials such as titanium alloy, make full use of resources, and solve the problem of resource hiding. Laser-cladding technology has been widely used in the remanufacturing of blades due to its ability to fabricate high-performance alloy surfaces on metal substrates without affecting the properties of the matrix. In order to solve the problem that the grinding precision is difficult to guarantee due to the deformation and residual distribution of the blade in laser cladding remanufacturing, the self-adaptive grinding process of abrasive belt is repaired based on online inspection and reconstruction model. Firstly, the distribution of theoretical measuring points is planned based on the curvature of cross-section curve, and then the theoretical measurement points are adaptively extracted according to the improved firefly algorithm, so that the CMM measurement path planning of laser cladding and remanufacturing blades is realized. Taking the layer as the unit, the measurement data are processed, and the iterative nearest point algorithm is used for data registration to realize the laser-cladding remanufacturing blade measurement data processing. On this basis, the blade surface model is obtained based on NURBS interpolation. Finally, a laser cladding and remanufacturing blade of an aero-engine was tested. The experimental results show that the blade surface roughness is 0.4 μm, the blade edge accuracy is less than 0.05 mm, and the blade edge error is less than 10%. The experimental results show that this method can effectively solve the grinding process of laser-cladding remanufacturing blade.

A 3D measuring path planning strategy for intelligent CMMs based on an improved ant colony algorithm

Coordinate measuring machines (CMMs) are being subjected to an increasing number of intelligent requirements due to mass manufacturing in the industry. It is important to plan the 3D measuring path for a CMM to meet the requirements of multi-objective measurements. A stable and fast three-dimensional (3D) path planning algorithm is desirable to improve the detection efficiency of a CMM. This paper establishes a 3D ant colony map for the measurement space. Then, an improved ant colony algorithm that can converge to the optimal path more rapidly than the standard ant colony algorithm is proposed. Finally, a new path re-optimization algorithm (RE-OP) and the new space collision detection algorithm are proposed. The simulation experiments show that the improved ant colony algorithm can steadily and rapidly obtain the optimal security path and can improve the detection efficiency of CMMs.

Research on the Algorithm of Measurement Path Planning for Inner Wall of Air-Intake Pipe Based on Spraying Robot System

To solve the problems with spraying over the inner wall of air-intake pipe, this paper introduces an algorithm of measurement path planning based on the spraying robot system and the laser displacement sensor technology. Scanning measurement path planning is the premise and basis of model construction and spray. Traditional methods, such as arc length extrapolation and polynomial are applicable only for the measurement of a plane curve with finite maximum curvature. Drawing references from existing method, this paper focuses on the pre-scanning measurement method for different types of cross-section curves. Algorithm simulation and model reconstruction show that this study solves the problem of collision avoidance for scanning measurement of the inner wall of air-intake pipe.

The Adaptive Machining of the Leading and Trailing Edges of Precision Forging Blades Based on the On-Machine Measurement

Blades are important components of aviation-engine, with complex shape and high precision machining. The radius of curvature of the leading and trailing edges of the precision forging blades is small and the curvature changes fast. In this paper, the adaptive machining scheme about the leading/trailing edge of the precision forging blade is proposed. Firstly, the measurement model based on theoretical model of the blade is established. Secondly, according to the measurement model, the measurement path planning is proposed. Thirdly, measurement data processing and registration, then blade model reconstructed to generate the new NC code for machining.

A Method of Coordinate Measuring Path Planning Based on Polychromatic Sets

In order to improve the intelligent level of path planning in coordinate measurement, the algorithm of path planning based on theory of polychromatic sets and ant colony algorithm is proposed. The model of the relation about measured geometrical features, probe angles and inspection planes is established, and the sub path is got by grouping for the global path on the basis of conjunctive operation of polychromatic sets. The global path is optimized by planning the sub paths with ant colony algorithm. The practical example verified the validity and reliability of the proposed method.

Research on Path Planning Method for On-Line Measurement of Blisk

The blisk is an important component of aviation engine and its level of machining and measurement will directly affect the application properties of the engine. This paper investigates the on-line measurement of single blade of the blisk. The section lines and the points to be measured are determined by using the empirical formula based on B-spline theory and feature point extraction algorithm. The probe-blade interference problem is solved by dividing the measurement area into different sectors and the posture angle of the probe in different inference-free sector domain is determined. The CATIA simulation is conducted to validate the correctness of the path planning algorithm for measurement. The measuring path planning plays an important role in improving the efficiency and reducing the cost of measurement.

An Obstacle Avoidance Algorithm for Path Planning Based on Inspection MBD Model

Aiming at measuring path planning, based on inspection MBD (Model Based Definition) models of the measured parts, size and position information of the parts features are generated. Global coordinate equations of the features are established. In measuring process, probe heads should move along the outer normal vector, and the path should be the shortest. Under these constraint condictons, the obstacle avoidance path are created between the probe head starting points and the inspected features origin points. Finally, an example is given to verify the algorithm, which offers a base for the whole path planning considering the change of the probe heads and their direction.

Investigation of a measurement scheme based on IGES

The integration research of measuring machine and CAD information, just CMM/CAD integration technology, is far behind the information integration of mechanical processing and CAD. With the rapid development of information integration industry and in the manufacturing process of the parts with complex curve surface, it is crucial to integrate the measurement and machining procedures based on IGES as that IGES is a general ANSI standard of information exchange for CAD/CAM among different computer systems. The measuring path planning determines the realization of measuring each sampling point and the completion of all sampling points safely and effectively by using measuring equipment. Based on IGES in this paper, the calculation method of normal direction at the location of sample point is studied for different surfaces, so as to improve the measuring precision. Then the calculation strategy for the positioning points and the measuring range is established, and the identification method for the topological relation between surfaces is also researched for improving the measuring efficiency and security. At last, the measuring sequence of the sampling points to be planned reasonably based on TSP is given. It is believed that the research results can provide some useful contributions towards the development of automated inspection task planning and systems, especially for coordinate measuring machines.